remove index.html links in wg README that links to wg folders (where README.md will be automatically detected and rendered in GitHub UI (#241)

Author: ramin

cips/wgs/README.md

@@ -3,8 +3,6 @@
 Here you will find all working groups
 and their meeting notes and recordings, if available.
 
-<!-- I don't really understand why `./da/README.md` etc. don't work, but they don't work locally for me  -->
-
-- [Data Availability](./da/index.html)
-- [Interface](./interface/index.html)
-- [ZK](./zk/index.html)
+- [Data Availability](./da)
+- [Interface](./interface)
+- [ZK](./zk)